pthread_mutex_trylock overwrites global variable
 

Hi all,

I am new to linux and got problem with pthread_mutex_trylock(). I have used mutex in my code. When I try to call pthread_mutex_trylock() on RECURSIVE type of mutex it overwrites adjacent memory location (that is global variable of type structure say x, memory allocated using malloc()).
Actually I put 'awatch' hardware watch on variable x, when i call pthread_mutex_trylock() it changes variable 2 members of x with message like

0x 0xSomeAdd from libpthread.so.0

and that causes segmentation fault in later part of code...Is it any known issue with pthread?? if you want I can paste complete code here...I have searched enough on libpthread but couldnt find anything specific....

Configurations are
CentOs 5 on VM Workstation

>uname -a

Linux SamCentOs.itpl 2.6.18-128.1.6.el5 #1 SMP Wed Apr 1 09:19:18 EDT 2009 i686 i686 i386 GNU/Linux

>rpm -aq | grep libc

glibc-2.5-34
glibc-headers-2.5-34
glibc-common-2.5-34
glibc-devel-2.5-34


>rpm -aq | grep gcc
gcc-c++-4.1.2-44.el5
gcc-4.1.2-44.el5
libgcc-4.1.2-44.el5
gcc-gfortran-4.1.2-44.el5


and the strange thing is the code works fine with following configuration

Linux avSam 2.6.11-1.1369_FC4 #1 Thu Jun 2 22:55:56 EDT 2005 i686 i686 i386 GNU/Linux

glibc-2.3.5-10
glibc-devel-2.3.5-10
glibc-common-2.3.5-10
glibc-headers-2.3.5-10
glibc-kernheaders-2.4-9.1.94

libgcc-4.0.0-8
gcc-4.0.0-8
gcc-c++-4.0.0-8
gcc-java-4.0.0-8

surrely something you're not doing the right way...
compile your code with -g (I'm assuming you're using GCC) and run your program with "alleyoop" memory checker. It certainly point you the problem.
If you don't find it by yourself, post code here certainly somebody will take look...